<!DOCTYPE html>
<html>
<head>
  <meta name="viewport" content="width=device-width">
  <style>
    fencedframe {
      width: 314px;
      height: 271px;
    }
  </style>
</head>
<body>
  <fencedframe src="viewport_child.html"></fencedframe>
</body>
</html>
